Hypercalcemia in prostate cancer with positive neuron-specific enolase stain

Hypercalcemia is a common complication of malignant diseases with or without bone metastasis. Hypercalcemia in prostate cancer is rarely seen. The exact mechanism of prostate cancer-related hypercalcemia is still uncertain. Secretion of parathyroid hormone-related peptides (PTH-rP) is thought to be one of the possible mechanisms. We reported a rare case of prostate cancer with hypercalcemia (13 mg/dL). Bone marrow biopsy showed metastatic adenocarcinoma. The cells were also positive for neuron-specific enolase, which is the specific marker for neuroendocrine cell. The finding suggested that the prostate cancer cell derived from the neuroendocrine cell, which might synthesize PTH-rP and be responsible for the observed hypercalcemia.